Abstract

The energy required to form an electron‐hole pair in gallium phosphide has been measured using GaP p‐njunction diodes made from high‐purity‐level GaP materials. The values of εGaP for several GaP diodes for alpha particles ranged from 6.35 to 6.75 eV, with an average value of 6.54 ± 0.13 eV at 300°K. This value is smaller than that obtained by Goldstein and is very close to the value of 6.56 eV calculated from the experimental relationship ε = 2.596Eg + 0.714 (eV), which was derived previously from the experimental values of ε for Ge, Si, GaAs, and CdTe.